Field of the Invention
Exemplary embodiments of the present invention relate to a signal processing apparatus for a wheel speed sensor, and more particularly, to a signal processing apparatus for a wheel speed sensor, which monitors a current input to a wheel speed sensor so as to prevent the current from being excessively supplied to the wheel speed sensor. That is, the exemplary embodiments of the present invention relate to the signal processing apparatus for a wheel speed sensor, capable of monitoring the current input to the wheel speed sensor in a duplex manner.
Description of the Related Art
In recent years, an example of mounting an anti-lock brake system to a vehicle increases rapidly. This is to previously prevent accidents by preventing loss of steering force or rotation of the vehicle caused by fixing of wheels when the vehicle is rapidly braked in the event of danger during traveling and by preventing sliding of the vehicle caused by fixing of the wheels when the vehicle is braked on an icy road.
The above anti-lock brake system provides stable braking force for the vehicle, which is rapidly braked or travels on the unstable road such as a snowy road or a rainy road, since an electronic control unit of the anti-lock brake system repeatedly controls locking and unlocking between a brake pad and a brake disk according to wheel rotation speed of the vehicle. Therefore, it is necessary to accurately detect the wheel rotation speed, and to detect whether or not a wheel speed sensor fails so as to properly control the wheel rotation speed in response to the detected result.
That is, a study has been carried out since the wheel speed sensor is required to have an accurate operation and it is necessary to monitor whether or not the wheel speed sensor is abnormally operated, in order for the vehicle to safely travel in a recent vehicle environment.
For example, Korean Patent Laid-open Publication No. 10-2009-0078401 discloses a technique in which a circuit of monitoring a current input to a wheel speed sensor is eliminated by preventing the current from being excessively supplied to the wheel speed sensor using a current mirror.
However, there is a concern about safety since it is not determined whether or not the wheel speed sensor and the circuit of monitoring the current input thereto fail in the above Patent Document.